<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>外边距</title>
    <style>
        /* margin-外边距 两个盒子合并外边距*/
        div {
            width: 200px;
            height: 200px;
            background-color: red;
            margin: 10px;
        }
    </style>
</head>

<body>
    <div></div>
    <div></div>
</body>

</html>